Sorry,
It has nothing to do with normalisation. It is a program for scientific applications.
Data values are broken into column to allow multiple linear regression and multivariate regression trees computations.
Even SPSS the most well-known statistic sw uses the same approach and data structure that my software uses.
Probably I should use another data structure but would not be as eficient and practical as the one I use now.
Many thanks
-Evandro
On 08 Nov 2005 05:30:07 -0800, Randal L. Schwartz <merlyn@xxxxxxxxxxxxxx> wrote:
>>>>> "Evandro's" == Evandro's mailing lists (Please, don't send personal messages to this address) < listasjr@xxxxxxxxx> writes:
[I would have replied to your personal address, but I'm not about
to copy it from a footer.]
Evandro's> I'm doing a PhD in data mining and I need more than 1600 columns. I got an
Evandro's> error message saying that I can not use more than 1600 columns.
Evandro's> It is happening because I have to change categorical values to binary
Evandro's> creating new columns. Do you know if oracle can handle it?
/me boggles
You are doing a PhD in data mining, and you have a table that needs
more than 1600 columns?
/me gasps
What are they *teaching* these days?
If you have a design that has more than 20 or so columns, you're
probably already not normalizing properly. There just aren't *that*
many attributes of a object before you should start factoring parts of
it out, even if it means creating some 1-1 tables.
In programming, if I ever see someone name a sequence of variables,
like "thing1" and "thing2", I know there's going to be trouble ahead,
because that should have been a different data structure. Similarly,
I bet some of your columns are "foo1" and "foo2". Signs of brokenness
in the design.
Or do you really have 1600 *different* attributes, none of which have
a number in their name? That requires a serious amount of
creativity. :)
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Evandro M Leite Jr
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University of Southampton, UK
Personal website: http://evandro.org
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